Size is no measure of ambition. Big ideas don’t have to take up a lot of space, and bad ideas don’t get better when they’re amplified. Both kinds inevitably turn up in the 54th Venice Biennale, June 4-Nov. 27, 2011, which involves artists and curators from a record 89 countries, not counting the "collateral events" or the museum shows surrounding it. If the breadth of this exposition bites off a larger slice of the cake that is art today than any single person could possibly chew, it does have some tasty icing to make swallowing easier.